Continuous flow separation chamber with weir disk

ABSTRACT

A continuous flow centrifuge bowl includes a rotatable outer body, and a top and bottom core that are rotatable with the outer body. The bottom core has a wall extending proximally from a bottom wall. The proximally extending wall is radially outward from at least a portion of the top core and, together with the top core, defines a primary separation region in which initial separation of the whole blood occurs. The bowl may also have a secondary separation region located between the top core and the outer body, and a rotary seal that couples an inlet port and two outlet ports to the outer body. The inlet port may be connected to an inlet tube that extends distally into a whole blood introduction region. Additionally, one of the outlet ports may be connected to an extraction tube that extends into a region below the bottom core.

PRIORITY

This patent application claims priority from U.S. Provisional PatentApplication No. 61/722,506, filed Nov. 5, 2012, entitled, “ContinuousFlow Separation Chamber,” and naming Matthew Murphy, Dominique Uhlmann,Edward Powers, Michael Ragusa, and Etienne Pages as inventors, thedisclosure of which is incorporated herein, in its entirety, byreference.

TECHNICAL FIELD

The present invention relates to whole blood separation chambers, andmore particularly to continuous flow separation chambers and methods ofusing the same.

BACKGROUND ART

Apheresis is a procedure in which individual blood components can beseparated and collected from whole blood withdrawn from a subject.Typically, whole blood is withdrawn through a needle inserted into avein of the subject's arm and into a cell separator, such as acentrifugal bowl. Once the whole blood is separated into its variouscomponents, one or more of the components can be removed from thecentrifugal bowl. The remaining components can be returned to thesubject. In some instances, the remaining components can be returnedalong with optional compensation fluid to make up for the volume of theremoved component. The process of drawing and returning continues untilthe quantity of the desired component has been collected, at which pointthe process is stopped. A central feature of apheresis systems is thatthe processed but unwanted components are returned to the donor. Bloodcomponents separated may include, for example, a high density componentsuch as red blood cells, an intermediate density component such asplatelets or white blood cells, and a lower density component such asplasma.

As mentioned above, many prior art apheresis systems use a centrifugebowl to separate and collect the individual blood components. In suchsystems, the whole blood is drawn into the bowl and separated into thevarious components (e.g., within a separation region). As the bowlcontinues to fill with whole blood, red blood cells sediment towards theouter diameter of the bowl, causing a plasma interface (e.g., theinterface between the red blood cells and plasma) to move towards thecenter of the bowl. When the plasma interface reaches a certain point,plasma is pushed out of the bowl and may be collected in one or morecollection bags. Blood will continue to fill the bowl until the plasmainterface reaches a certain position. At this point, the introduction ofwhole blood into the bowl is stopped.

After the introduction of whole blood is stopped, the collected plasmamay be recirculated to the bowl in order to remove a layer of plateletsformed within the bowl. Once the platelets are collected, many prior artsystems then collect and/or return the remaining contents of the bowl tothe patient. The process is then repeated in a batch-like/intermittentmanner until a target amount of blood component (e.g., red blood cells,platelets, plasma, etc.) is collected.

SUMMARY OF THE EMBODIMENTS

In accordance with one embodiment of the present invention, a centrifugebowl for continuous separation of whole blood (e.g., into red bloodcells and plasma) may include an outer body rotatable about alongitudinal axis of the centrifuge bowl. Within the outer body, thebowl can have a top core and a bottom core. The top core may berotatable and coaxial with the outer body. The bottom core may have abottom wall and a proximally extending wall that extends from the bottomwall and is radially outward from at least a portion of the top core.The proximally extending wall and a portion of the top core can define aprimary separation region in which separation of the whole blood begins.The bowl may also have a secondary separation region located between thetop core and the outer body.

In some embodiments, the bowl may have an inlet port for introducingwhole blood into the centrifuge bowl, and an inlet tube fluidlyconnected to and extending distally from the inlet port. The inlet tubemay introduce the whole blood into an introduction region (between thetop core and the bottom core). Additionally, the bowl can have a firstblood component outlet port and a second blood component outlet port.The first blood component outlet port may be for drawing a first bloodcomponent out of the centrifuge bowl. A first blood component extractiontube may extend from the first blood component outlet port and throughthe bottom core to a region below the bottom core. The second bloodcomponent outlet port may be fluidly connected to the secondaryseparation region and may be configured to allow a second bloodcomponent to exit the centrifuge bowl. A centrifuge bowl rotary seal maybe attached to the outer body and couple the inlet port, first bloodcomponent outlet port, and second blood component outlet port to theouter body.

The primary separation region may be fluidly connected to the secondaryseparation region, and there may be a first blood component extractionregion located between the bottom wall of the bottom core and a bottomof the outer body. The first blood component extraction tube may extendinto the first blood component extraction region. Additionally, theproximally extending wall may be configured to prevent whole blood fromentering the first blood component extraction region. The bowl may alsoinclude a fluid path way that (1) extends from the introduction regionto the primary separation region, (2) fluidly connects the inlet tubeand the primary separation region, and (3) is located between the bottomwall of the top core and the upper surface of the bottom core.

The bowl may also include a seal located between the first bloodcomponent extraction tube and the bottom core, and a bypass seal (e.g.,a rotary seal). The top core may include a chimney extending through thetop core along the longitudinal axis of the centrifugal bowl. The inlettube and first blood component extraction tube may extend through thechimney. The bypass seal may be located between the outer diameter ofthe inlet tube and the inner diameter of the chimney, and may isolatethe introduction region from the chimney. The first blood componentextraction tube may be coaxial with the inlet tube.

On a shoulder of the bowl/outer body, the bowl may have an opticalsensor that monitors an interface between the first blood component andthe second blood component. The optical sensor may control the operationof a first blood component pump based upon a location of the interface.The first blood component pump may draw the first blood component fromthe bowl.

The bowl may also have a weir disk extending inward from a neck portionof the outer body. The second blood component may flow over the weirdisk into the neck portion of the outer body prior to exiting thecentrifuge bowl via the second blood component outlet port. The bottomsurface of the weir disk and a top surface of the top core may define asecond blood component channel that fluidly connects the secondaryseparation region and the second blood component outlet port.

In accordance with further embodiments, a centrifuge bowl for continuousseparation of whole blood may include an outer body that is rotatableabout a longitudinal axis of the centrifuge bowl, a top core, and aseparation region. The top core may be located within and may berotatable with the outer body. The top core may also be coaxial with theouter body and have a chimney extending through it along thelongitudinal axis of the centrifuge bowl. The separation region may belocated between the top core and the outer body, and rotation of thecentrifuge bowl may separate the whole blood within the separationregion into a first blood component (e.g., red blood cells) and a secondblood component (e.g., plasma).

The centrifuge bowl may also have an inlet port for introducing wholeblood into the centrifuge bowl. The inlet port may be fluidly connectedto an inlet tube that extends distally from the inlet port and throughthe chimney. The inlet tube may introduce the whole blood into anintroduction region. There may be a bypass seal (e.g., a rotary seal)between an outer diameter of the inlet tube and an inner diameter of thechimney to isolate the introduction region from the chimney. A firstblood component outlet port (e.g., in fluid communication with theseparation region) may be used to draw the first blood component out ofthe centrifuge bowl. A first blood component extraction tube may becoaxial with the inlet tube and extend from the first blood componentoutlet port to a first blood component extraction region. Additionally,the bowl may include a second blood component outlet port fluidlyconnected to the separation region and configured to draw a second bloodcomponent from the centrifuge bowl. A centrifuge bowl rotary sealattached to the outer body may couple the inlet port, first bloodcomponent outlet port, and second blood component outlet port to theouter body.

In addition to the top core, in some embodiments, the bowl may alsoinclude a bottom core located within and rotatable with the outer body.The bottom core may be located between the bottom surface of the outerbody and the top core. The first blood component extraction region maybe located between the bottom wall of the bottom core and a bottom ofthe outer body, and may fluidly connect the first blood componentextraction tube and the separation region. The first blood componentextraction tube may extend through the bottom core and into the firstblood component extraction region. Additionally, there may be a sealmember located between the first blood component extraction tube and thebottom core to prevent leakage between the first blood componentextraction tube and the bottom core.

In some embodiments, the bowl may include an optical sensor located on ashoulder of the outer body. The optical sensor may monitor an interfacebetween the first blood component and the second blood component withinthe separation region, and control the operation of a first bloodcomponent pump based upon a location of the interface. The first bloodcomponent pump may draw the first blood component from the centrifugebowl.

Additionally, the bowl may have a weir disk extending inward from theneck portion of the outer body. The second blood component may flow overthe weir disk into the neck portion of the outer body prior to exitingthe centrifuge bowl via the second blood component outlet port. The weirdisk and a top surface of the top core can define a second bloodcomponent channel that fluidly connects the separation region and thesecond blood component outlet port.

The centrifuge bowl may also have a bottom core with a bottom wall and aproximally extending wall that extends from the bottom core. Theproximally extending wall may be radially outward from at least aportion of the top core. The proximally extending wall and a portion ofthe top core may define a primary separation region that is fluidlyconnected to the secondary separation region. The bowl may also have afluid path that extends between a bottom wall of the top core and anupper surface of the bottom core, and fluidly connects the inlet tubeand the primary separation region. A first blood component extractionregion (located between the bottom wall of the bottom core and a bottomof the outer body) may fluidly connect the first blood componentextraction tube and the separation region. The proximally extending wallmay prevent whole blood from entering the first blood componentextraction region. The introduction region may be located between thetop core and the bottom core.

In accordance with still further embodiments, a centrifuge bowl forcontinuous separation of whole blood may include an outer body, a topcore, and a separation region. The outer body may be rotatable about alongitudinal axis of the centrifuge bowl, and may have a main bodydefining an interior cavity, a neck portion extending proximal to themain body, and a shoulder connecting the main body and the neck portion.The top core may be located within and rotatable with the outer body.The top core may also be coaxial with the outer body and include achimney extending through it along the longitudinal axis of thecentrifuge bowl. The separation region may be located between the topcore and the outer body, and rotation of the centrifuge bowl mayseparate the whole blood within the separation region into a first bloodcomponent and a second blood component.

The bowl may also include an inlet port, a first blood component outletport, and a second blood component outlet port. The inlet port mayintroduce whole blood into the centrifuge bowl, and may be fluidlyconnected to an inlet tube that extends distally from the inlet port andthrough the chimney to introduce the whole blood into an introductionregion. The first blood component outlet port may draw a first bloodcomponent out of the centrifuge bowl, and may have a first bloodcomponent extraction tube that extends from the first blood componentoutlet port to a first blood component extraction region. The secondblood component outlet port may be fluidly connected to the separationregion and may be configured to draw a second blood component from thecentrifuge bowl. The bowl may also have a rotary seal that is attachedto the outer body and fluidly couples the inlet port, first bloodcomponent outlet port, and second blood component outlet port to theouter body.

Additionally, the bowl may also have a weir disk extending inward fromthe neck portion of the outer body. In such embodiments, the secondblood component may flow over the weir disk and into the neck portion ofthe outer body prior to exiting the centrifuge bowl via the second bloodcomponent outlet port. The weir disk and the top surface of the top coremay define a second blood component channel that fluidly connects theseparation region and the second blood component outlet port.

Located between the bottom surface of the outer body and the top core,the bowl may also have a bottom core that is rotatable with the outerbody. The first blood component extraction region may be located betweenthe bottom wall of the bottom core and a bottom of the outer body, andmay fluidly connect the first blood component outlet tube and theseparation region. The first blood component extraction tube may extendthrough the bottom core and into the first blood component extractionregion, and a seal member located between the first blood componentextraction tube and the bottom core may prevent leakage between thefirst blood component extraction tube and the bottom core.

The bottom core may have a bottom wall and a proximally extending wallthat is radially outward from at least a portion of the top core. Theproximally extending wall and at least a portion of the top core maydefine a primary separation region that is fluidly connected to thesecondary separation region. The bowl may also have a fluid pathwayfluidly connecting the inlet tube and the primary separation region. Thefluid pathway may extend between a bottom wall of the top core and anupper surface of the bottom core. The proximally extending wall mayprevent whole blood from entering the first blood component extractionregion.

The outer body may include an optical sensor that (1) monitors aninterface between the first blood component and the second bloodcomponent within the separation region, and (2) controls the operationof a first blood component pump based upon a location of the interface.The first blood component pump may draw the first blood component fromthe centrifuge bowl. The inlet tube and the first blood componentextraction tube may extend through the chimney and may be coaxial. Thebowl may also include a bypass seal (e.g., a rotary seal) between anouter diameter of the inlet tube and an inner diameter of the chimneythat isolates the introduction region from the chimney.

In accordance with additional embodiments, a centrifuge bowl forcontinuous separation of whole blood may include an outer body rotatableabout a longitudinal axis of the bowl, a top core located within androtatable with the outer body, and a separation region located betweenthe top core and the outer body. The outer body may have a main bodydefining an interior cavity, a neck portion extending proximal to themain body, and a shoulder connecting the main body and the neck portion.The top core may be coaxial with the outer body and may include achimney extending through it along the longitudinal axis of thecentrifuge bowl. Rotation of the centrifuge bowl may separate the wholeblood within the separation region into a first blood component and asecond blood component.

The bowl may also have a rotary seal attached to the outer body andfluidly coupling an inlet port, a first blood component outlet port, anda second blood component outlet port to the outer body. The inlet portmay be used to introduce whole blood into the centrifuge bowl, and maybe fluidly connected to an inlet tube. The inlet tube may extenddistally from the inlet port and through the chimney to introduce thewhole blood into an introduction region. The first blood componentoutlet port may be used to draw the first blood component out of thecentrifuge bowl, and may include a first blood component extraction tubeextending from the first blood component outlet port to a first bloodcomponent extraction region. The second blood component outlet port maybe fluidly connected to the separation region and may be used to draw asecond blood component from the centrifuge bowl.

Moreover, the bowl may also have an optical sensor located on theshoulder of the outer body. The optical sensor may monitor an interfacebetween the first blood component and the second blood component withinthe separation region, and control the operation of a first bloodcomponent pump based upon a location of the interface. The first bloodcomponent pump may draw the first blood component from the centrifugebowl.

A bottom core located below the top core can have a bottom wall and aproximally extending wall. The first blood component extraction regionmay be located between the bottom wall of the bottom core and a bottomof the outer body, and may fluidly connect the first blood componentoutlet tube and the separation region. The first blood componentextraction tube may extend through the bottom wall of the bottom core,and the bowl may include a seal member located between the first bloodcomponent extraction tube and the bottom wall of the bottom core. Theseal member may prevent leakage between the first blood componentextraction tube and the bottom core.

The proximally extending wall may be radially outward from at least aportion of the top core, and may define a primary separation region withat least a portion of the top core. The primary separation region may befluidly connected to the secondary separation region, and the bowl mayinclude a fluid pathway (e.g., extending between a bottom wall of thetop core and an upper surface of the bottom core) that fluidly connectsthe inlet tube and the primary separation region. The separation chambermay be in fluid communication with the second blood component outlet.

The first blood component extraction tube and the inlet tube may becoaxial and may extend through the chimney. The bowl may include abypass seal (e.g., a rotary seal) between an outer diameter of the inlettube and an inner diameter of the chimney that isolates the introductionregion from the chimney. Additionally, a weir disk extending inward fromthe neck portion of the outer body may define a second blood componentchannel with a top surface of the top core. The second blood componentchannel may fluidly connect the secondary separation region and thesecond blood component outlet port. The second blood component may flowover the weir disk into the neck portion of the outer body prior toexiting the centrifuge bowl via the second blood component outlet port.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing features of embodiments will be more readily understood byreference to the following detailed description, taken with reference tothe accompanying drawings, in which:

FIG. 1 schematically shows a cross-sectional view of a continuous flowcentrifuge bowl in accordance with illustrative embodiments of thepresent invention.

FIG. 2 schematically shows a cross-sectional view of the lower portionof the centrifuge bowl shown in FIG. 1 with an alternative bottom core,in accordance with illustrative embodiments of the present invention.

FIG. 3 schematically shows a cross-sectional view of a bypass sealwithin the centrifuge bowl shown in FIG. 1, in accordance withillustrative embodiments of the present invention.

FIG. 4 schematically shows a cross-sectional view of the top portion ofthe centrifuge bowl shown in FIG. 1, in accordance with illustrativeembodiments of the present invention.

FIG. 5 is a schematic diagram of a continuous flow blood processingsystem using the centrifuge bowl shown in FIG. 1, in accordance withillustrative embodiments of the present invention.

FIG. 6 schematically shows a cross-sectional view of an alternativecontinuous flow centrifuge bowl in accordance with illustrativeembodiments of the present invention.

FIG. 7 schematically shows a cross-sectional view of the lower portionof the centrifuge bowl shown in FIG. 6, in accordance with illustrativeembodiments of the present invention.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

In illustrative embodiments, a continuous flow separation chamber isable to process and separate whole blood into its various components,and allows for the extraction of multiple blood components (e.g., redblood cells, plasma, etc.) simultaneously and while the separationchamber is spinning. In this manner, various embodiments of the presentinvention are able to continuously process whole blood and avoid thedrawbacks of the batch/intermittent processes described above.

FIG. 1 schematically shows a cross-section of a continuous flowseparation chamber (e.g., a centrifuge bowl 110), in accordance withsome embodiments of the present invention. The bowl 110 has an outerbody 120 that defines the structure of the bowl 110 and an inner volumeinto which the whole blood may be introduced for processing. The outerbody 120, in turn, includes a main wall 122 that defines a main bodyportion 123, a neck portion 126, and shoulder portion 124 that connectsthe main body portion 123 and the neck portion 126. As discussed ingreater detail below, the bowl 110 is rotatable about an axis 130 inorder to separate the whole blood into its various components.

Within the interior of the outer body 120, the bowl can include a numberof cores that displace some of the volume within the outer body 120,create separation regions in which the whole blood separates, and createa number of fluid paths/channels within the bowl 110. For example, thebowl 110 may include a top core 140 that fills a significant portion ofthe inner volume and may be frusto-conical in shape. The top core 140includes a top surface 144, a bottom wall 146, and a side wall 142 thatextends between the top surface 144 and the bottom wall 146. The sidewall 142 may be spaced from the main wall 122 (e.g., the main body 123)to create a separation region (e.g., a secondary separation region 115)between the side wall 142 of the top core 140 and the main wall 122 ofthe outer body 120. Additionally, the top core 140 can have a chimney148 extending through the center from the top surface 144 to the bottomwall 146. As discussed in greater detail the chimney 148 may serve as achannel through which a number of tubes (e.g., an inlet tube and anextraction tube) can pass.

The bowl 110 may also include a bottom core 160 (FIG. 2) located belowthe top core 130 (e.g., distal to the top core 130). The bottom core 160may include a bottom circular wall 162 with an opening 166 extendingthrough it (e.g., near the center of the circular wall 162). The bottomcore 160 may also have a vertical wall 164 that extends upward (e.g.,proximally) from the bottom circular wall 162. As shown in FIGS. 1 and2, the vertical wall 164 is located near the outer diameter of thebottom circular wall 162 and may extend upwards such that it is radiallyoutward from the side wall 142 of the top core 140. The annular spacebetween the side wall 142 of the top core 140 and the vertical wall 164creates a primary separation region 170 in which separation of wholeblood begins (discussed in greater detail below). Although similar, itis important to note that the bottom core 160 shown in FIG. 2 is analternative embodiment of the bottom core 160 shown in FIG. 1 (e.g., itis thinner than that shown in FIG. 1).

As best shown within FIG. 4, within the neck portion 126 of the outerbody 120, the centrifuge bowl 110 can include a upper skirt 182 and alower skirt 184 both extending radially outward from the center of thebowl 110. Together, the upper skirt 182 and the lower skirt 184 can forman effluent skirt 180 through which one or more of the separated bloodcomponents can flow and exit the bowl 110 (e.g., via the second bloodcomponent outlet 230, discussed in greater detail below). To that end,the upper skirt 182 and the lower skirt 184 may be spaced from oneanother such that an effluent channel 186 is formed between the skirts182/184. The exiting blood component can flow through the effluentchannel 186 to reach the second blood component outlet 230.

In order to facilitate the transfer of fluids (e.g., whole blood andblood components) in and out of the centrifuge bowl 110, the bowl 110can have an inlet and one or more outlets. For example, the bowl 110 mayinclude an inlet 190 that may be used to introduce whole blood into thebowl 110. In many blood processing procedures, it is desirable tointroduce the whole blood into an area near the bottom of the bowl 110.To that end, some embodiments of the present invention may also includean inlet tube 195 that extends downward from the inlet 190, through thechimney 148 in the top core 140, and into an introduction region 200located between the top core 140 and the bottom core 160. Additionally,the bottom core 160 (e.g., the circular wall 162) may be spaced from thebottom 146 of the top core 140 to create a channel 205 extending fromthe introduction region 200 to the primary separation region 170. Thecentrifugal force created by spinning the bowl 110 may cause the wholeblood entering the introduction region 200 to flow through the channel205 and into the primary separation region 170.

It is important to note that problems can arise if the whole blood orother fluid introduced into the bowl 110 (e.g., into the introductionregion 200) flows back up into the chimney 148 (e.g., instead oftraveling towards the outer diameter of the bowl 110 and into theseparation regions). For example, if this “bypass” occurs while the bowl110 is being filled, unseparated red blood cells may flow up the chimney148, and contaminate the effluent plasma exiting the bowl 110. If thebypass occurs during a surge step (e.g., to remove platelets from thebowl 110, discussed in greater detail below), plasma may travel up thechimney 148 instead of carrying away the platelets. In order to avoidthis “bypass” and isolate the introduction region 200 from the chimney148 in the top core 130, some embodiments of the present invention caninclude a bypass seal 210 (FIG. 3) located between the outer diameter ofthe inlet tube 195 and the inner diameter of the chimney 148. The bypassseal 210 can be a rotary seal to allow the top core 130 (and the bowl110) to rotate relative to the inlet tube 195 (which does not rotateduring bowl operation).

In addition to the inlet 190, the bowl 110 can also include a firstblood component outlet 220 and a second blood component outlet 230. Asthe name suggests, the first blood component outlet 220 can be used toremove a first blood component (e.g., red blood cells) from the bowl110. Additionally, in a manner similar to the inlet 190, the first bloodcomponent outlet 220 may be fluidly connected to a tube (e.g., a firstblood component extraction tube 225) that extends downward from thefirst blood component outlet 220, through the chimney 148, through theopening 166 in the bottom core 160 (e.g., within the bottom circularwall 162), and into a first blood component extraction region 240located below the bottom bore 160 (e.g., between the bottom core 160 andthe bottom of the bowl 110). To prevent leakage past the bottom core 160(e.g., through opening 166), the bowl 110 can also have a seal 222(e.g., a rotary seal) between the first blood component extraction tube225 and the opening 166. As discussed in greater detail below, a pumpcan draw the first blood component out of the first blood componentextraction region 240, through the first blood component extraction tube225 and out of the first blood component outlet 220.

The second blood component outlet 230 may be used to remove the secondblood component (and perhaps a third) from the bowl 110. To that end,the second blood component outlet 230 may be fluidly connected to theeffluent channel 186 through the effluent skirt 180. Therefore, when thesecond blood component is pushed towards the neck portion 126 (e.g., asdiscussed in greater detail below), the second blood component can flowthrough the effluent channel 186 and out of the second blood componentoutlet 230.

As best shown in FIGS. 1 and 4, the centrifuge bowl 110 may include arotary seal 250 that connects the ports (e.g., the inlet 190, firstblood component outlet port 220, and second blood component outlet port230) to the outer body 120 of the bowl 110. The rotary seal 250 allowsthe bowl 110 (and the top core 140 and bottom core 160) to spin whilethe inlet 190, first blood component outlet 220, and second bloodcomponent outlet 230 remain stationary.

It is important to note that in some applications, in order to extractthe first blood component (e.g., red blood cells) from the bowl 110(e.g., from the first blood component extraction region 240), a largenegative pressure may be required to overcome the centrifugal forcecreated as the bowl 110 spins. For example, it was discovered that theradius of the air cylinder defined by the diameter 182 of the effluentskirt 180 (e.g., a cylinder of air below the effluent skirt 180) drivesthe negative force required to draw out the first blood component. Insome applications, the pressures required to draw out the first bloodcomponent can be greater than 500 mmHG (P=ρgr, where ρ is the density ofthe fluid, g is the centrifugal force and r is the radius of the aircylinder), which is impractical for any type of available pumpingtechnology.

In order to reduce the pressure required to withdraw the first bloodcomponent, some embodiments of the present invention can include a weirdisk 260 (FIG. 4) that extends radially inward from the bottom of theneck portion 126 of the outer body 120. The weir disk 260 essentiallycreates a wall that forces fluid leaving the bowl 110 to a smallerdiameter defined by the inner diameter 262 of the opening 264 throughthe weir disk 260. In this manner, the weir disk 260 essentiallydecouples the diameter of the effluent skirt 180 from the radius of theair cylinder, which, in turn, reduces the radius of the air cylinder(which is now defined by diameter 262 of the opening 264 in the weirdisk 260) and the pressure required to withdraw the first bloodcomponent from the bowl 110.

As shown in FIG. 4, the weir disk 260 creates a fluid channel 270between the weir disk 260 and the top surface 144 of the top core 140.As the bowl 110 fills with fluid, the fluid will flow through the fluidchannel 270 between the weir disk 260 and the top surface 144 of the topcore 140 until it reaches the opening 264 in the weir disk 260. Thefluid may then “roll over” the weir disk 260 (e.g., similar to theoverflow of a dam), and fill the region above the weir disk 260 (e.g.,the neck portion 126 of the bowl 110) until it comes in contact with theeffluent skirt 180. The fluid (e.g., the second blood component) maythen be pushed from the bowl 110 into the effluent channel 186 and intothe second blood component outlet 230.

During blood processing it is important to know not only how full thebowl 110 is but also the location of the red blood cell/plasma interfacewithin the secondary separation chamber 115. To that end, someembodiments may include an optical system 280 located on the shoulder124 of the outer body 120. The optical system 280 may include an LED(e.g., a red LED) that emits a beam (e.g., approximately 1-2 mm indiameter) that illuminates a small area of the shoulder 124.Additionally, the optical system 280 may also include an optical sensorthat is focused on the illuminated area of the bowl shoulder 280.

As the plasma/cell interface encroaches on this illuminated area, thesignal received back at the sensor decreases. The optical system 180 maybe in communication with a control system of the blood processingdevice, and when the optical system 280 identifies that this signal hasdecreased by some predetermined amount (e.g. 10%), the control systemmay increase the speed of a pump (e.g., a red blood cell pump, discussedin greater detail below) that is drawing the first blood component outof the bowl by some predetermined amount (e.g. 5 ml/min). If the readingfrom the optical sensor continues to decrease, the control system maycontinue to increase the speed of the pump. When the output from theoptical sensor begins to plateau and no longer change, the controlsystem will maintain the speed of the pump. Conversely, if the outputsignal begins to increase, the control system will slow down the pump,pushing the interface further in towards the area of illumination. Inthis manner, various embodiments of the invention are able to monitorand control the location of the plasma/cell interface to ensure that theinterface remains in the optimal location within the bowl 110.

FIG. 5 schematically shows an exemplary blood processing system 510utilizing the centrifuge bowl 110 described above and shown in FIG. 1.FIG. 5 will be discussed in conjunction with an exemplary bloodprocessing method. First, whole blood may be drawn from source (e.g., apatient, a blood storage bag, etc.), through a draw line 520, and into astorage container (e.g., draw bag 530) using a donor pump 540. Duringthis draw step, the donor pump 540 may run in a clockwise direction andvalves V1 and V3 may be open to allow the whole blood to flow into thedraw bag 530, and valves V2 and V4 may be closed to prevent the wholeblood from entering a return line 550. Also, while the whole blood isbeing drawn from the source, an anticoagulant pump 560 may drawanticoagulant through an anticoagulant line 565 from an anticoagulantsource (not shown). The anticoagulant may mix with the drawn whole bloodprior to reaching the draw bag 530. In some embodiments, the draw pump540 may draw approximately 75-80 mL of whole blood at approximately 120mL/min during this initial draw phase.

Once the initial draw step has commenced and a sufficient amount ofanticoagulated whole blood is collected in the draw bag 530, a bowl pump570 may begin to draw anticoagulated whole blood from the draw bag 530via line 575. As the bowl pump 570 draws the anticoagulated whole bloodfrom the bag 530, valve V4 may be opened to allow the anticoagulatedwhole blood to flow into line 575, and valves V5 and V9 may be closed toprevent the anticoagulated whole blood from flowing into the plasma bag580 via the plasma recirculation line 585 and/or the platelet bag 590via the platelet line 595. In order to ensure that a sufficient volumeof anticoagulated whole blood remains within the draw bag 530 (e.g., tomaintain a continuous flow of anticoagulated whole blood to the bowl110), the bowl pump 570 may draw the anticoagulated whole blood from thebag at a rate slower than that of the donor pump 540. For example, thebowl pump 570 may draw at a rate of 60 mL/min as compared to the donorpump's rate of 120 mL/min. The bowl 110 will continue to fill until theoptical system 280 detects the presence of the plasma/cell interface.

As the anticoagulated whole blood enters the bowl 110 through the inlet190, it will flow down the inlet tube 195 and into the introductionregion 200. Once in the introduction region 200, the centrifugal forcesfrom the spinning of the bowl 110 will cause the anticoagulated wholeblood to flow through the channel 205 between the top core 140 andbottom core 160 and into the primary separation region 170 (e.g.,between the side wall 142 of the top core 140 and the proximallyextending wall 164 of the bottom core), where separation of theanticoagulated whole blood into its individual components (e.g., plasma,platelets, red blood cells) begins.

As additional anticoagulated whole blood is introduced into the bowl110, the whole blood will flow into the secondary separation region 115where the anticoagulated whole blood continues to separate. For example,as the whole blood enters the secondary separation region 115 of thebowl 110, the centrifugal forces cause the heavier cellular componentsof the blood to sediment from the lighter plasma component of the blood.This results in the cell/plasma interface mentioned above. The red bloodcells are by far the most numerous of the cellular components of bloodand the most dense, resulting in a layer of concentrated red blood cellsat the outermost diameter of the bowl 110. As filling continues, theother cellular components of blood begin to become apparent. Thesecellular components are primarily platelets, leukocytes and peripheralhematopoietic progenitor stem cells. These cells may have a range ofdensities between that of the red blood cells and plasma. Therefore theytend to sediment in a layer between the red blood cell layer and plasmalayer. As this layer grows, it is visually apparent as a solid whitelayer which is known as a buffy coat.

As the bowl 110 continues to fill with whole blood, the red blood cellswill continue to sediment to the outermost diameter, flow over theproximally extending wall 164 on the bottom core 160, and begin to fillthe area between the bottom core 160 and the bottom of the bowl 110.Additionally, the intermediate cells of the buffy coat will continue toaccumulate at the red blood cell/plasma interface, and the plasmainterface will move inward towards the center of the bowl 110. When thebowl 110 is full, the plasma will flow through the fluid channel 270between the weir disk 260 and the top surface 144 of the top core 140,over the weir disk 260, and will exit the bowl 110 via the effluentchannel 186 and the second blood component outlet 230.

As the plasma exits the bowl 110, the majority of the plasma may passthrough line 610, valve V8, line 630 and into a return bag 640. However,a small volume of plasma (e.g., 175-200 mL over the length of theprocedure) may be sequestered within the plasma bag 580. To sequesterthis plasma in the plasma bag 580, the operator or the control systemcan open valve V7 to allow some of the plasma exiting the bowl 110 toenter line 650 and flow into the plasma bag 580. As discussed in greaterdetail below, the sequestered plasma in the plasma bag 580 will be usedduring a surge elutriation procedure to remove the platelets from thebowl 110.

As mentioned above, the bowl 110 is a continuous flow bowl that allowsthe continuous processing of whole blood without the need tointermittently stop. To that end, various embodiments of the presentinvention also extract red blood cells from the bowl 110 as additionalwhole blood is introduced (e.g., while simultaneously extractingplasma). For example, once the red blood cells have collected under thebottom core 160 (e.g., in the first blood component extraction region240), the red blood cell pump 660 can draw red blood cells inward of theair cylinder diameter (e.g., corresponding to the diameter of theeffluent skirt 180 or the opening 264 through the weir disk 180, ifequipped), into the first blood component extraction region 240, up thefirst blood component extraction tube 225 and out of the first bloodcomponent outlet 220. As the red blood cells leave the bowl 110, theywill pass through line 670 and into the return bag 640. While the redblood cell pump 660 extracts the red blood cells, the optical system 280will monitor the location of the plasma/cell interface and will controlthe flow rate of the red blood cell pump 660 to adjust the location ofthe interface as necessary (e.g., it will speed up the pump 660 if thesensor output decrease and slow down the pump 660 if the sensor outputincreases).

Once the donor pump 540 has drawn a predetermined volume of whole bloodfrom the source (e.g., 80 mL), the system 510 will stop the draw stepand begin to return some of the blood components (e.g., red blood cellsand plasma) that have been collected in the return bag 640. For example,the system 510 will reverse the direction of the donor pump 540, closevalves V1 and V3, and open valves V2 and V10. This will cause the donorpump 540 to begin drawing (e.g., at 120 mL/min) the plasma and red bloodcells within the return bag 640 through line 680, valves V10 and V2,through a return line 550 and back to the source (e.g., back to thepatient). This return phase will continue until a predetermine volume ofred blood cells and plasma are returned to the subject, for example, 80mL. The system 510 may then alternate the draw and return phases untilthe procedure is complete.

It is important to note that, because this is a continuous system,anticoagulated whole blood is continuously drawn from the draw bag 530and into the bowl 110, even during the return phase. As mentioned above,this can be accomplished by first drawing a bolus volume of whole bloodfrom the subject, collecting the bolus volume of whole blood within thedraw bag 530, and drawing the whole blood from the draw bag at a slowerrate than the draw and return steps (e.g., the bowl pump 570 draws theanticoagulated whole blood at 60 mL/min and the donor pump 540 draws thewhole blood from the subject and returns the red blood cells and plasmato the subject at 120 mL/min). Therefore, the draw bag always has asufficient volume of anticoagulated whole blood from which the bowl pump570 can draw.

The whole blood processing may continue until a desired volume ofplatelets has accumulated within the bowl 110. When the blood processingis complete, the system 510 may then perform a surge elutriation processusing the sequestered plasma in order to extract the highly concentratedplatelet product. For example, the bowl pump 570 can draw the plasmawithin the plasma bag 580, through plasma recirculation line 585 andvalve V9, and into the bowl 110 (e.g., via the inlet 190). To elutriatethe platelets, the flow rate of plasma is gradually increased. As theflow rate is increased, the effluent plasma passes through a line sensor620 (located on line 610) that monitors the fluid exiting the bowl 110.At some point in this ramping up of plasma flow rate, the drag forcecreated by the plasma flow overcomes the centrifugal force caused by thebowl rotation, and the platelets are carried away from the buffy coat inthe flowing plasma. The line sensor 620 may then detect the presence ofcells (e.g., as the fluid exiting the bowl 110 changes from plasma toplatelets), and the system 510 (or the user) can close valve V7 and openvalve V6 to allow the platelets to flow into the platelet line 595 andinto the platelet bag 590.

After the elutriation process and after the platelets are collectedwithin the platelet bag 590, the system 510 may stop the bowl 110 andreturn the contents of the bowl 110 to the donor For example, the system510 may turn on the red blood cell pump 660 to draw the contents of thebowl 110 into the return bag 640 (via line 670). The donor pump 540 maythen draw the contents of the return bag 640 through line 680, andreturn the components via the return line 550.

It should be noted that, although the blood processing method discussedabove draws whole blood from and returns the contents of the bowl to adonor, some embodiments may not draw from and/or return to a donor.Rather, in some embodiments, the whole blood may be drawn from a wholeblood storage container, and the contents of the bowl 110 may bereturned to the whole blood storage container (or a different bloodstorage container).

It is also important to note that although the centrifuge bowl 110discussed above and shown in FIG. 1 has a sloped wall 142 on the topcore 140 (e.g., it is angled such that the diameter of the top core 140increases from the top surface 144 to the bottom 146), other embodimentscan have different configurations. For example, as shown in FIGS. 6 and7, some embodiments of the bowl 710 can have a top core 720 with a sidewall 722 having a straight section 724 and an angled/sloped section 726.The straight walled section 724 can extend a distance from the bottom728 of the top core 720 and may be located radially inward from theproximal wall 164 of the bottom core 160. The primary separation region730 may be located between (and defined by) the straight walled section724 of the top core 720 and the proximally extending wall 164 of thebottom core 160. The angled/sloped wall/section 726 can extend from thetop of the straight walled portion 724 to the top surface 740 of the topcore 720.

The embodiments of the invention described above are intended to bemerely exemplary; numerous variations and modifications will be apparentto those skilled in the art. All such variations and modifications areintended to be within the scope of the present invention as defined inany appended claims.

What is claimed is:
 1. A centrifuge bowl for continuous separation ofwhole blood comprising: an outer body rotatable about a longitudinalaxis of the centrifuge bowl, the outer body having a main body definingan interior cavity, a neck portion extending proximal to the main body,and a shoulder connecting the main body and the neck portion, the outerbody having a main wall; a top core located within and rotatable withthe outer body, the top core being coaxial with the outer body andincluding a chimney extending through the top core along thelongitudinal axis of the centrifuge bowl; a separation region locatedbetween the top core and the outer body, rotation of the centrifuge bowlseparating the whole blood within the separation region into a firstblood component and a second blood component; an inlet port forintroducing whole blood into the centrifuge bowl; an inlet tube fluidlyconnected to and extending distally from the inlet port and through thechimney, the inlet tube configured to introduce the whole blood into anintroduction region; a first blood component outlet port for drawing afirst blood component out of the centrifuge bowl; a first bloodcomponent extraction tube extending from the first blood componentoutlet port to a first blood component extraction region; a second bloodcomponent outlet port fluidly connected to the separation region and fordrawing a second blood component from the centrifuge bowl; a weir diskextending from the main wall and radially inward into the neck portionof the outer body, the second blood component flowing over the weir diskinto the neck portion of the outer body prior to exiting the centrifugebowl via the second blood component outlet port; and a centrifuge bowlrotary seal attached to the outer body and fluidly coupling the inletport, first blood component outlet port, and second blood componentoutlet port to the outer body.
 2. A centrifuge bowl according to claim1, further comprising a blood component channel defined by a bottomsurface of the weir disk and a top surface of the top core, the bloodcomponent channel fluidly connecting the separation region and thesecond blood component outlet port.
 3. A centrifuge bowl according toclaim 1, further comprising a bottom core located within and rotatablewith the outer body, the bottom core located between a bottom of theouter body and the top core, the first blood component extraction regionlocated between a bottom wall of the bottom core and the bottom of theouter body, the first blood component extraction region fluidlyconnecting the first blood component extraction tube and the separationregion.
 4. A centrifuge bowl according to claim 3, wherein the firstblood component extraction tube extends through the bottom core.
 5. Acentrifuge bowl according to claim 4, further comprising a seal memberlocated between the first blood component extraction tube and the bottomcore, the seal member preventing leakage between the first bloodcomponent extraction tube and the bottom core.
 6. A centrifuge bowlaccording to claim 1, wherein the separation region is in fluidcommunication with the second blood component outlet port.
 7. Acentrifuge bowl according to claim 1, further comprising an opticalsensor located on the shoulder of the outer body, the optical sensorconfigured to monitor an interface between the first blood component andthe second blood component within the separation region, the opticalsensor configured to control the operation of a first blood componentpump based upon a location of the interface.
 8. A centrifuge bowlaccording to claim 7, wherein the first blood component pump isconfigured to draw first blood component from the centrifuge bowl.
 9. Acentrifuge bowl according to claim 1, wherein the first blood componentis red blood cells and the second blood component is plasma.
 10. Acentrifuge bowl according to claim 1, further comprising a bottom corehaving a bottom wall and a vertically extending wall extending from thebottom wall, the vertically extending wall being radially outward fromat least a portion of the top core.
 11. A centrifuge bowl according toclaim 10, further comprising a primary separation region defined by thevertically extending wall and at least a portion of the top core.
 12. Acentrifuge bowl according to claim 11, wherein the primary separationregion is fluidly connected to the separation region.
 13. A centrifugebowl according to claim 11, further comprising a fluid pathway fluidlyconnecting the inlet tube and the primary separation region.
 14. Acentrifuge bowl according to claim 13, wherein the fluid path wayextends between a bottom wall of the top core and the bottom wall of thebottom core.
 15. A centrifuge bowl according to claim 10, wherein thefirst blood component extraction region is located between the bottomwall of the bottom core and a bottom of the outer body, the first bloodcomponent extraction tube extending into the first blood componentextraction region.
 16. A centrifuge bowl according to claim 10, whereinthe proximally extending wall prevents whole blood from entering thefirst blood component extraction region.
 17. A centrifuge bowl accordingto claim 1, wherein the first blood component extraction tube is coaxialwith the inlet tube.
 18. A centrifuge bowl according to claim 1, whereinthe inlet tube and first blood component extraction tube extend throughthe chimney.
 19. A centrifuge bowl according to claim 18, furthercomprising a bypass seal between an outer diameter of the inlet tube andan inner diameter of the chimney, the bypass seal isolating theintroduction region from the chimney.
 20. A centrifuge bowl according toclaim 19, wherein the bypass seal is a rotary seal.
 21. A centrifugebowl according to claim 1, wherein the main wall includes a neck portionwall that defines the neck portion, and a shoulder portion wall thatdefines the shoulder portion.